This is an open-label, dose-escalating multi-center trial to determine the safety, tolerability, and pharmacokinetic parameter of 3 does of DAB389IL-2 in patients with sever psoriasis. The doses were chosen because previous studies have domonstrated that adverse experiences occur more frequently at higher doses and efficacy has been present at all doses. This protocol explores and lower and varied treatment schedule. Efficacy will also be assessed. A total of forty-five patient will be assigned in a dose escalating manner to one of the 3 dose groups (0.5, 1.5, and 5.0 ug/kg/day). Drug is administered 3 day every other week for 8 weeks.